It's no secret to men that close-fitting shirt collars and tightly tied neckties are one of the most nettlesome--if trivial--inconveniences associated with being male. Now, researchers at the Cornell University College of Human Ecology say these dress habits may harm vision too.
In a study involving measurement of the tightness of shirt collars and ties and vision clarity in several groups of men, researchers found that neckties tied so tightly that they reduced the natural circumference of the neck measurably cut visual acuity for such tasks as reading.
The study, reported in the journal Human Factors, speculated that the relationship between necktie tightness and vision may be traced to reduction in blood flow through the carotid arteries, which supply the brain and run up the neck fairly close to the skin. Researchers said 67% of the men studied were wearing shirts or ties that were too tight. The tie was at fault far more often than the shirt collar.
An obvious preventive step: Unfasten the top button of your shirt and loosen the knot of your tie.
Dietary Fat, Cholesterol
There's no shortage of research on the effects of blood cholesterol levels on the risk of heart disease for men, but for women--especially pre-menopausal women--it remains a field in which few studies have been done and in which conclusions about men are presumed to hold true for women.
It came as something of a surprise, then, that in a new project examining the relationship of fat in the diet and cholesterol in the blood of young, healthy women, a 50% reduction in dietary fat had almost no effect on cholesterol.
What this may mean is unclear, but the leader of the National Cancer Institute team that conducted the study said the results emphasize that a great deal remains unknown about the precise relationship between fat consumed in food and levels of fatty chemicals in the bloodstream.
The researcher, D. Yvonne Jones, reported that while she continues to believe men and women alike should reduce dietary fat intake, the finding about the ineffectiveness of fat reduction in influencing cholesterol in women took her by surprise.
She said noted that most research studies on the subject focus on men--in whom the dietary fat-cholesterol interrelationship appears to be more clear cut.
Jones' new study was published in the American Journal of Clinical Nutrition. It focused on a total of 31 women in their late 20s whose cholesterol levels to begin with were well within healthful guidelines. The key subgroup of 15 women in whom dietary intervention was tried had an average total cholesterol reading of 180 milligrams--well below the 200 level generally accepted as indicative of good health.
At first, the women were given diets in which 40% of total calories were fat. Then the diets were changed, cutting the fat to 20%. All of the diets included items from all the traditional food groups and were considered normal in the context of U.S. nutrition. But the reduction in fat, the Jones team found, was accompanied by just a 12% decline in cholesterol--a change the researchers found to be insignificant.
"I really expected that there would be more of an effect of such a drastic drop in fat," Jones said from Bethesda, Md. Whether women whose cholesterol levels were higher than the healthy group studied would experience the same insignificant dietary reduction is not known. Jones said she is following the study up to see if women after menopause have changes in the diet-cholesterol relationship.
Exercise and Osteoporosis
Today's women are increasingly aware of the hazards and risks of osteoporosis--and they are equally interested in ways they can minimize their risk of sustaining the sometimes-debilitating bone loss associated with the disease.
Highly promoted risk-assessment clinics and the dispute over whether taking calcium supplements has any preventive effect are two early entries on the list of controversies as osteoporosis awareness increases.
Now, a new question has been raised about yet another of the tenets of the osteoporisis-prevention faith: Can regular exercise in pre-menopausal adulthood can avert later damage to the spine from the disease?
Writing in an editorial in the Journal of the American Medical Assn., four UC San Francisco researchers have cautioned that while the idea that exercise can prevent osteoporosis is still an inviting concept, proof that this belief is valid is still lacking.
The researchers said regular exercise is, beyond question, still a good idea--to maintain overall health and to speed recovery from injuries that may be suffered in a fall. And they say it may well turn out to be true that exercise--especially load-bearing exercise--is an osteoporosis prevention. The four scientists reviewed several dozen studies of the relationship between exercise and osteoporosis.